80 Psyche [April 



7. Calypteres fringed with dusky hairs; lunule bare; base of tarsi alone yellow; 



arista bare 8 



Calypteres yellow, with yellow fringe; lunule hairy; tarsi largely or wholly 

 yellow; arista microscopically pubescent; third antennal joint large, longer 

 than broad; front of 9 slightly narrowed anteriorly; epistome projecting. 

 Eur., La.*; Id., Aldrich laticornis Meigen. 



8. Third antennal joint orbicular, not longer than broad; front broadly quadrate, 



not at all narrowed anteriorly, the lunula broadly arched; face retreating, the 

 epistome retracted, the face very wide, its sides white-pruinose; tarsi notice- 

 ably flattened. Eur.; Id. Aldrich parvicornis Zetterstedt. 



Third antennal joint longer than broad; front of 9 narrowed anteriorly, the 

 lunula highly arched; epistome projecting; side of face less pruinose and 

 face not unusually wide. Eur.; Id. Aldrich, Mont.* viridana Meigen. 



9. Legs entirely black or blackish 10 



At least base of tarsi yellowish 13 



10. Head, thorax and abdomen metallic blue-green; antennae greatly surpassing 



the oral margin. S. Am., Mex chalybea Wiedemann. 



Head and thorax jet black, or at least but little metallic; antennae reaching 

 the oral margin 11 



11. Vertex opaque, with three shining spots 12 



Vertex black; abdomen metallic black; legs and antennae fuscous. Brazil, 



Cuba, N. H. {nigra Wied., 1830, nee. Meig. 1826) . . wiedemanni Towiisend. 



12. Anterior cross-vein beyond the apex of the auxiliary vein; calypteres pale 



yellow. Eur.*; Wash., Wise. Aldrich vaginalis Fallen. 



Anterior cross-vein before the apex of the auxiliary vein; calypteres fuscous. 

 Eur., Alaska hyalipennis Zetterstedt. 



13. Calypteres with white cilia 14 



Calypteres with blackish cilia 15 



14. Head, thorax and abdomen deep shining black; wings tinged with light brown- 



ish yellow; metatarsi yellow. W. Ind longicornis AYilliston. 



Thorax and abdomen more or less metallic blue- violet or bluish green; face 

 entirely white-pruinose, nearly flat in profile; wings hyaline; tarsi yellow 

 except the tip brown. Mass., N. H., N. Y., N. J., Pa., Ga., La.*, Ind„ 

 111.*, S. Dak.*, Ariz., Wash.*, Mex. [polita Say (1830); ccendea Walker 

 (1849) rufitarsis Macquart (1851)] (fig. 15) polita Say (1830) 



15. Thorax pilose; front shining black. Eur., Ga., Id.* tarsata Fallen. 



Hairs of thorax relatively short; front matte-black. Eur., Alaska. 



albitarsis Zetterstedt. 



Genus Palloptera Fallen. 



1. Cross-veins not bordered with brown; thorax gray-pollinose; auxiliary and 



first vein and apex of wing brownish. Alaska, Wash.* (fig. 21) 



terminalis Loew. 



Cross-veins bordered with brown; thorax and abdomen yellowish 2 



2. First vein wholly included in the brown color, costa wholly or almost entirely 



brown 3 



